﻿<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" >
<head>
<title>Pi calculation</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
	@import "../../../dojo/resources/dojo.css";
	@import "../../../dijit/tests/css/dijitTests.css";
</style>
<script type="text/javascript" src="../../../dojo/dojo.js" djConfig="isDebug: true"></script>
<script type="text/javascript">
dojo.require("dojox.gfx");

var iterations = 0, inCounter = 0, totalCounter = 0,
	interval, surface;

var compute = function(){
	var x = Math.random();
	var y = Math.random();
	var pointX = Math.round(x * 300);
	var pointY = Math.round(y * 300);

	var pointColor = "red";
	if(x*x + y*y < 1){
		inCounter++;
		pointColor = "green";
	}
	
	surface.createCircle({cx: pointX, cy: pointY, r: 3}).
		setFill(pointColor).setStroke({color: pointColor, width: 2});

	totalCounter++;
	
	if(totalCounter % 100 == 0 || totalCounter == iterations){
		var PI = parseFloat(inCounter / totalCounter) * 4;
		var error = (PI - Math.PI) / Math.PI * 100;	// in %
		dojo.byId("result").innerHTML = PI + " (error = " + error.toFixed(2) + 
			"%) after " + totalCounter + " points";
	}

	if(totalCounter == iterations){
		clearInterval(interval);
		dojo.byId("startButton").disabled = false;
	}
};

var go = function(){
	dojo.byId("startButton").disabled = true;
	dojo.byId("result").innerHTML = "&nbsp;";
	inCounter = totalCounter = 0;
	iterations = parseInt(0 + parseInt(dojo.byId("iterations").value), 10);
	interval = setInterval(compute, 20);
};

var init = function(){
	surface = dojox.gfx.createSurface("test", 300, 300);
	dojo.connect(dojo.byId("startButton"), "onclick", this, go);
};

dojo.addOnLoad(init);

</script>
</head>
<body>
<h1>PI demo</h1>
<p>Visualization of calculating PI using the Monte Carlo method.</p>
<p>
<label>Iterations:</label> <input type="text" name="iterations" value="500" id="iterations"/>
<input type="button" name="start" value="start" id="startButton" />
</p>
<p><span style="color:green">Green</span>: x^2 + y^2 &lt;= 1, <span style="color:red">Red</span>: x^2 + y^2 &gt; 1</p>
<p>Estimated value for PI: <span id="result" style="font-weight: bold"></span></p>
<div id="test" style="width: 300px; height: 300px;border:1px solid black"></div>
<p>That's all Folks!</p>
</body>
</html>
